This invention relates to a spherical-coordinate micromanipulator for the operating element of a vitrectomy instrument, wherein motion of the operating element is controllable in any desired direction of the coordinate system.
Vitrectomy is a new method of operation in the field of vitreous surgery. With respect to access or entry into the volume of the corpus vitreum, one distinguishes between "open sky vitrectomy" and "vitrectomy via pars plana". Vitrectomy through the pars plana makes use of special motorized instruments for the purpose of cutting the pathologically modified vitreous body into small pieces, and at the same time drawing them off. In detail, the present methods are described by H. D. Gnad in an article entitled, "The Present Status of Vitrectomy", published in Klinische Monatsblatter fur Augenheilkunde, 166 (1975), pages 817 to 825. And in the journal "Archives of Ophthalmology", Volume 88, September 1972, pages 325 to 329, B. R. Straatsma et al. have described a spherical-coordinate micromanipulator for vitrectomy operations. The disadvantage of the known micromanipulator is that the movement of the vitrectomy instrument is carried out manually, without any auxiliary energy. For each of the three coordinate directions involved, a mechanical operating element is provided. This type of motion control is so cumbersome, due to the need for continuous change between the three operating elements, that the user can guide the vitrectomy instrument to the target point only after various manipulations and frequent change of the grip of the hand.